The Environmental Protection Agency (EPA) set forth guidelines for states to follow in designing and running vehicle inspection and maintenance (I/M) programs. The guidelines are designed to reduce pollutants in the air that are produced by vehicles having defective or improperly working emissions systems. The guidelines for automobile emissions testing programs set forth the minimum requirements to satisfy the Clean Air Act (CAA). Under the CAA, the states must periodically inspect vehicles that travel on the roadways. Included in the periodic inspection for newer vehicles is the checking of the on-board diagnostic system.
Vehicles emissions inspections programs have traditionally analyzed the vehicle exhaust under simulated driving conditions. One way to simulate driving conditions is by placing the vehicle on rollers and running the vehicle at various speeds. Placing the vehicle on rollers and running the vehicle at selected speeds is undesirable because it is inconvenient, time consuming, and potentially dangerous.
Another method of performing a vehicle emissions inspection is to analyze the data stored on the on-board diagnostic system that was gathered during actual driving conditions. All vehicles manufactured since 1996 are required to have an on-board vehicle diagnostic system. The on-board vehicle diagnostic system includes one or more computer modules that are used to control various components, such as the engine, transmission, anti-lock brake system etc. The on-board vehicle diagnostic systems monitor and store data indicative of emissions levels, such as, for example, data from the oxygen sensor, the catalytic converter, the EGR valve, etc., that are obtained during actual driving conditions over a period of time and during key “off” conditions. Once the vehicle has been driven for a sufficient period of time for the on-board diagnostic system to fully evaluate the emissions system, the on-board diagnostic system sets a status flag. The status flag, or readiness code, is used to verify that error codes have not been cleared immediately prior to having the vehicle inspected.
A typical I/M program for 1996 and later models includes a manual examination of the components and an electronic examination of the on-board diagnostic system. First, the inspector enters the vehicle identification number into a computer terminal, so that the vehicle identification number can be reported to the state along with the results of the emissions test. The vehicle identification number is either entered manually, or entered by scanning a bar code label that may be located on the vehicle door. After entering the VIN number, the vehicle is pulled forward and the inspector performs a visual check of the dashboard display, status indication, (or the malfunction indicator light “MIL”) and selected emissions control components. Finally, the inspector performs an inspection of the on-board vehicle diagnostic system. Typically, an “Off-Board Tool,” (OBT) such as a scan tool, code reader or similar hand-held instrument is used to extract data from the vehicle on-board diagnostic system in the form of Diagnostic Trouble Codes (DTCs), monitors, etc.
“Off-Board Tools,” such as, for example, scan tools, and code reader are testing devices that interface with vehicle diagnostic systems to access, display, and/or print vehicle diagnostic information. On-Board Diagnostics Version II Scan Tools are one commonly known type of scan tool and are governed by a number of standards, such as, for example, SAE J1978 Rev. April 2002 and SAE J1979 Rev. April 2002.
Optical scanners are known and include bar code scanners. Generally, there are two types of bar code scanners, less-expensive contact scanners, and more expensive non-contact scanners. The less-expensive contact scanners, also known as manual scanners, or one-pass scanners require close, or actual physical contact, between the scanner and the bar code. Manual scanners or one-pass scanners include, for example, light pen bar code readers. As the name implies, non-contact scanners do not require direct contact with the bar code. Non-contact scanners include, for example, scanners that use a CMOS camera sensor, and scanners that use lasers and osculating mirrors. The latter are often found in hand-held devices at checkout lines.
Typically, test centers that scan in VIN numbers utilize a scanner at one station and an OBT at a second station. Placing the vehicle at one location to enter the vehicle identification number and moving the vehicle to a second station to retrieve data from the vehicle diagnostic system increases the time and space required to perform an emissions test.